PTFE (Polytetrafluoroethylene) The combination of chemical and physical properties of PTFE is a consequence of its true fluorocarbon structure. This unusual structure leads to a material which has an almost universal chemical inertness; complete insolubility in all known solvents below 300°C; excellent thermal stability; and unsurpassed electrical properties, including low dielectric loss, low dielectric constant and high dielectric strength. Furthermore, PTFE does not embrittle at very high or at very low temperatures.